Edwin t



EDWIN T. GREENFIELD, OF NEW YORK, N. Y., ASSIGNOR TO THE INTERIOR CONDUIT AND INSULATION COMPANY, OF SAME PLACE.

ARMORED ELECTRICAL CONDUIT.

SPECIFICATION forming part of Letters Patent No. 585,864, dated July 6, 1897.. Application filed December 10, 1896. Serial No. 615,116. (No model.)

To all whom it may concern: faces and to so line the tube T with these in- Be it known that I, EDWIN T. GREENFIELD, terior linings of one or more thicknesses O O a citizen of the United States, residing at New as to produce the desired insulation. WVhen York, in the county of New York and State more than one thickness is used, I prefer to 5 5 of New York, have made a new and useful have the linings break joints, as shown at J Invention in Armored Electrical Conduits, of J, Fig. 2. After the tube T has thus been which the following is a specification. provided with one or more interior linings My invention relates to that class of elecclosely adhering to its inner wall I prefer to trical conduits having a strong external prosubject it to a bath of molten pitch or asphalt 6o 10 tecting or armor tube and an inner tube or in such manner as to thoroughly coat the inlining of fibrous insulating material, such as ner lining and the outer surface of the tube is disclosed in United States Patent- No. T. This result is accomplished by successive 552,060, granted to me on December 24, 1895. clippings into the molten material in a man- I have found that in the practical use of ner well understoodby those skilled in the art. i 5 armored conduit-tubes in which the interior I do not limit myself to the use of the comlining is of fibrous insulating material under mercial article of trade known as oil-cloth certain conditions of temperature and moisfor lining the inner wall of an armored conture the insulating-lining will become perduit-tube, as I may use for this lining any colated with moisture to such an extent as to fibrous material which has been treated with 2o deteriorate its insulating capacity, and it was oil or with any insulating agent impervious with a view of overcoming this objectionable to moisture as, for instance, cotton, wool, or feature that the present invention was deother cloth fabric, paper, or, in fact, any vised. fibrous material which can be thoroughly sat- The invention will be fully understood by urated with a moisture-resisting agent, such 25 referring to the accompanying drawings, in as linseed-oil, or I may use in place of oilwhich cloth 0 a lining of any flexible fibrous mate- Figure 1 is a longitudinal sectional view of rial treated with rubber either on one or both an armored conduit-tube embodying my imsurfaces or throughout its meshes or mass, provements; and Fig. 2 is a transverse secmy invention being designed to comprehend, 8o 30 tional view thereof, taken on the line 0c 00, Fig. generically, the use of one or more linings in 1, and as seen looking in the direction of the an armored conduittube, which shall act as arrows from the right toward the left hand an insulating medium and which shall also side of the drawings. under ordinary conditions of temperature and Referring now to the drawings in detail, T usage be impervious to moisture and will 3 5 represents a protecting or armor tube, prefreadily yield or bend with the armor without erably of iron, and O 0 an interior lining rupturing or otherwise impairing the integclosely adhering to the inner wall thereof. rity or imperviousness of the moisture-resist- Thisinteriorliningis composedfpreferablypf ing agent. This conduit may be bent cold two strips of oil-cloth O O or any fibrous mawithout impairing its insulating and mois- 9o 40 terial which has been thoroughly subjected tureresisting qualities, which is a highly useto a bath of oil or any equivalent substance ful and important function in the work of inwhich renders it impervious to water. stalling the conduit; nor do I limit myself to Iprefer toconstruct myimproved electrical the method of manufacture of the above-deconduit in the manner disclosed in a prior scribed armored conduit-tube, as it is evident 45 patent granted to me by the United States to the skilled person that this operation may Patent Office on the 27th day of October, 1896, be Varied in several particulars and still reand bearing No. 570,165, substituting for the suit in the production of a conduit having an paper strips disclosed in said patent strips of external protecting-armor and an internal oil-cloth or other fibrous material saturated tube or lining of insulating material which 50 with oil or with an equivalent moisture-re is of a flexible nature and is impervious to sisting agent and painted on one or both surmoisturein addition to itsinsulating qualities.

Having thus described my invention, What I claim, and desire to secure by Letters Patent of the United States, is-

1. A conduit-tube composed of a metal armor and an interior lining of oil-cloth With ing also as an insulating medium, substantially as described.

4. A conduit-tube composed of a metal armor and one or more insulating-linings of fibrous material impregnated with a moistureresisting agent, said linings and moisture-re' sisting agent acting also as an insulating medium, substantially as described.

In testimony whereof I have hereunto subscribed my name this 8th day of December, 1896.

EDYVIN T. GREENFIELD.

Vitnessos:

' G. J. KINTNER,

M. M. ROBINSON. 

